- Added thread safety to texture loading in the software renderer

src/swrenderer/line/r_walldraw.cpp

@@ -515,6 +515,8 @@ namespace swrenderer
 		this->rw_pic = pic;
 		this->mask = mask;
 
+		Thread->PrepareTexture(pic);
+
 		if (rw_pic->GetHeight() != 1 << rw_pic->HeightBits)
 		{
 			ProcessWallNP2(walltop, wallbottom, texturemid, swall, lwall, top, bottom);

src/swrenderer/plane/r_flatplane.cpp

@@ -59,7 +59,7 @@ namespace swrenderer
 		}
 
 		drawerargs.SetSolidColor(3);
-		drawerargs.SetTexture(Thread->Viewport.get(), texture);
+		drawerargs.SetTexture(Thread, texture);
 
 		double planeang = (pl->xform.Angle + pl->xform.baseAngle).Radians();
 		double xstep, ystep, leftxfrac, leftyfrac, rightxfrac, rightyfrac;

src/swrenderer/plane/r_skyplane.cpp

@@ -198,8 +198,8 @@ namespace swrenderer
 		angle1 = (uint32_t)((UMulScale16(ang, frontcyl) + frontpos) >> FRACBITS);
 		angle2 = (uint32_t)((UMulScale16(ang, backcyl) + backpos) >> FRACBITS);
 
-		drawerargs.SetFrontTexture(viewport, frontskytex, angle1);
+		drawerargs.SetFrontTexture(Thread, frontskytex, angle1);
-		drawerargs.SetBackTexture(viewport, backskytex, angle2);
+		drawerargs.SetBackTexture(Thread, backskytex, angle2);
 		drawerargs.SetTextureVStep(uv_step);
 		drawerargs.SetTextureVPos(uv_pos);
 		drawerargs.SetDest(viewport, start_x, y1);

src/swrenderer/plane/r_slopeplane.cpp

@@ -80,7 +80,7 @@ namespace swrenderer
 		auto viewport = Thread->Viewport.get();
 
 		drawerargs.SetSolidColor(3);
-		drawerargs.SetTexture(Thread->Viewport.get(), texture);
+		drawerargs.SetTexture(Thread, texture);
 
 		lxscale = _xscale * ifloatpow2[drawerargs.TextureWidthBits()];
 		lyscale = _yscale * ifloatpow2[drawerargs.TextureHeightBits()];

src/swrenderer/r_renderthread.cpp

@@ -88,4 +88,38 @@ namespace swrenderer
 		else
 			return pal_drawers.get();
 	}
+
+	void RenderThread::PrepareTexture(FTexture *texture)
+	{
+		if (texture == nullptr)
+			return;
+
+		// Textures may not have loaded/refreshed yet. The shared code doing
+		// this is not thread safe. By calling GetPixels in a mutex lock we
+		// make sure that only one thread is loading a texture at any given
+		// time.
+		//
+		// It is critical that this function is called before any direct
+		// calls to GetPixels for this to work.
+
+		static std::mutex loadmutex;
+		loadmutex.lock();
+		try
+		{
+			texture->GetPixels();
+			const FTexture::Span *spans;
+			texture->GetColumn(0, &spans);
+			if (Viewport->RenderTarget->IsBgra())
+			{
+				texture->GetPixelsBgra();
+				texture->GetColumnBgra(0, &spans);
+			}
+			loadmutex.unlock();
+		}
+		catch (...)
+		{
+			loadmutex.unlock();
+			throw;
+		}
+	}
 }

src/swrenderer/r_renderthread.h

@@ -80,6 +80,9 @@ namespace swrenderer
 		short cliptop[MAXWIDTH];
 
 		SWPixelFormatDrawers *Drawers(RenderViewport *viewport);
+
+		// Make sure texture can accessed safely
+		void PrepareTexture(FTexture *texture);
 		
 	private:
 		std::unique_ptr<SWTruecolorDrawers> tc_drawers;

src/swrenderer/r_swcanvas.cpp

@@ -274,7 +274,7 @@ void SWCanvas::FillSimplePoly(DCanvas *canvas, FTexture *tex, FVector2 *points,
 
 	// Setup constant texture mapping parameters.
 	SpanDrawerArgs drawerargs;
-	drawerargs.SetTexture(viewport, tex);
+	drawerargs.SetTexture(&thread, tex);
 	if (colormap)
 		drawerargs.SetLight(colormap, 0, clamp(shade >> FRACBITS, 0, NUMCOLORMAPS - 1));
 	else

src/swrenderer/viewport/r_skydrawer.cpp

@@ -34,9 +34,10 @@ namespace swrenderer
 		dc_viewport = viewport;
 	}
 
-	void SkyDrawerArgs::SetFrontTexture(RenderViewport *viewport, FTexture *texture, uint32_t column)
+	void SkyDrawerArgs::SetFrontTexture(RenderThread *thread, FTexture *texture, uint32_t column)
 	{
-		if (viewport->RenderTarget->IsBgra())
+		thread->PrepareTexture(texture);
+		if (thread->Viewport->RenderTarget->IsBgra())
 		{
 			dc_source = (const uint8_t *)texture->GetColumnBgra(column, nullptr);
 			dc_sourceheight = texture->GetHeight();
@@ -48,14 +49,15 @@ namespace swrenderer
 		}
 	}
 
-	void SkyDrawerArgs::SetBackTexture(RenderViewport *viewport, FTexture *texture, uint32_t column)
+	void SkyDrawerArgs::SetBackTexture(RenderThread *thread, FTexture *texture, uint32_t column)
 	{
+		thread->PrepareTexture(texture);
 		if (texture == nullptr)
 		{
 			dc_source2 = nullptr;
 			dc_sourceheight2 = 1;
 		}
-		else if (viewport->RenderTarget->IsBgra())
+		else if (thread->Viewport->RenderTarget->IsBgra())
 		{
 			dc_source2 = (const uint8_t *)texture->GetColumnBgra(column, nullptr);
 			dc_sourceheight2 = texture->GetHeight();

src/swrenderer/viewport/r_skydrawer.h

@@ -15,8 +15,8 @@ namespace swrenderer
 	public:
 		void SetDest(RenderViewport *viewport, int x, int y);
 		void SetCount(int count) { dc_count = count; }
-		void SetFrontTexture(RenderViewport *viewport, FTexture *texture, uint32_t column);
+		void SetFrontTexture(RenderThread *thread, FTexture *texture, uint32_t column);
-		void SetBackTexture(RenderViewport *viewport, FTexture *texture, uint32_t column);
+		void SetBackTexture(RenderThread *thread, FTexture *texture, uint32_t column);
 		void SetTextureVPos(uint32_t texturefrac) { dc_texturefrac = texturefrac; }
 		void SetTextureVStep(uint32_t iscale) { dc_iscale = iscale; }
 		void SetSolidTop(uint32_t color) { solid_top = color; }

src/swrenderer/viewport/r_spandrawer.cpp

@@ -22,8 +22,10 @@ namespace swrenderer
 		spanfunc = &SWPixelFormatDrawers::DrawSpan;
 	}
 
-	void SpanDrawerArgs::SetTexture(RenderViewport *viewport, FTexture *tex)
+	void SpanDrawerArgs::SetTexture(RenderThread *thread, FTexture *tex)
 	{
+		thread->PrepareTexture(tex);
+
 		tex->GetWidth();
 		ds_xbits = tex->WidthBits;
 		ds_ybits = tex->HeightBits;
@@ -36,7 +38,7 @@ namespace swrenderer
 			ds_ybits--;
 		}
 
-		ds_source = viewport->RenderTarget->IsBgra() ? (const uint8_t*)tex->GetPixelsBgra() : tex->GetPixels();
+		ds_source = thread->Viewport->RenderTarget->IsBgra() ? (const uint8_t*)tex->GetPixelsBgra() : tex->GetPixels();
 		ds_source_mipmapped = tex->Mipmapped() && tex->GetWidth() > 1 && tex->GetHeight() > 1;
 	}
 

src/swrenderer/viewport/r_spandrawer.h

@@ -19,7 +19,7 @@ namespace swrenderer
 		void SetDestY(RenderViewport *viewport, int y) { ds_viewport = viewport; ds_y = y; }
 		void SetDestX1(int x) { ds_x1 = x; }
 		void SetDestX2(int x) { ds_x2 = x; }
-		void SetTexture(RenderViewport *viewport, FTexture *tex);
+		void SetTexture(RenderThread *thread, FTexture *tex);
 		void SetTextureLOD(double lod) { ds_lod = lod; }
 		void SetTextureUPos(dsfixed_t xfrac) { ds_xfrac = xfrac; }
 		void SetTextureVPos(dsfixed_t yfrac) { ds_yfrac = yfrac; }

src/swrenderer/viewport/r_spritedrawer.cpp

@@ -49,7 +49,7 @@ namespace swrenderer
 			return;
 
 		auto viewport = thread->Viewport.get();
-		
+
 		// Handle the linear filtered version in a different function to reduce chances of merge conflicts from zdoom.
 		if (viewport->RenderTarget->IsBgra() && !drawer_needs_pal_input) // To do: add support to R_DrawColumnHoriz_rgba
 		{
@@ -62,6 +62,8 @@ namespace swrenderer
 		dc_iscale = iscale;
 		dc_textureheight = tex->GetHeight();
 
+		thread->PrepareTexture(tex);
+
 		const FTexture::Span *span;
 		const uint8_t *column;
 		if (viewport->RenderTarget->IsBgra() && !drawer_needs_pal_input)
@@ -132,6 +134,8 @@ namespace swrenderer
 		dc_x = x;
 		dc_iscale = iscale;
 
+		thread->PrepareTexture(tex);
+
 		// Normalize to 0-1 range:
 		double uv_stepd = FIXED2DBL(dc_iscale);
 		double v_step = uv_stepd / tex->GetHeight();